No, it is the opposite. If you heat a glass of water in the microwave and then take it out, it won't get room temperature instantly, right? It takes time for objects to lose heat. It is realistic.
I'll enjoy this opportunity to tell you guys an idea I had. There should be a small blue arrow pointing down next to the temperature in the left-click menu that indicates that the temperature of the object is decreasing. New players might not understand that it takes time for the object to lose temperature, and they will think US is innacurate